Amorphous niobium oxide thin films

Ramirez, Giovanni; Rodil, S.E.; Mühl, S.; Turcio-Ortega, David; Olaya, Jhon J; Rivera, Margarita; Camps, E.; Escobar‐Alarcón, L.

doi:10.1016/j.jnoncrysol.2010.09.073

Cited by 88 publications

(55 citation statements)

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“…This finding does not generally contradict to a previous work by Habazaki and co-workers, 36 reporting that, during the anodizing of Al superimposed on Nb in barrier-type electrolytes, randomly 5 occurring NO nano-needles penetrate and irregularly mix with the upper alumina. However, the findings of our work reveal clearly that the ionic transport and anodic oxide growth become increasingly systematic when the Nb metal is reanodized through the alumina nanopores, which determine the local spots for 10 nucleation and growth of the NO nanocolumns. The enlarged and fully solid (root-free) tops of the NO protrusions (see also Figure 2c) result from merging the sub-nanochannels into a relatively wider pathway (Figure 8c), which is believed to happen because of the beginning of oxide growth inside the pores and the ion 15 migration within the outer part of the alumina cell walls.…”

Section: The Model Of Film Growthmentioning

confidence: 76%

“…5 This eventually confirms the presence of Al and Si in the column material and shows the degree of filing the pores by the niobium oxide. The high-resolution TEM images of fragments of the lamella are shown in Figure 6d, g, and h. On these images, the round spots are the areas impacted by the Ga ions used for 10 sputtering the sample surface in the FIB technique employed here. Three regions (a, b, and c) with dissimilar physical properties are well distinguished within the column section, the interpretation is given later in the text.…”

Section: Film Compositionmentioning

confidence: 99%

“…Surface sputtering was performed using a 3-keV Ar + ion beam at a current of 10 nA, rastered over an area of 200 × 200 μm. Both ion beams were directed under an angle of 45 o with respect to the surface normal and were aligned in such a way that the analyzed ions were taken from the middle of the sputtered 10 crater. The detection was made in the positive and negative ion modes.…”

mentioning

confidence: 99%

“…This characterizes the sensor as one of the fastest in the niche of nanostructured metal-oxide gas sensing films. 40,41 Comparative characteristics of best hydrogen-sensing 10 nanostructured active layers found in the are available in ESI). Further, the sensor resistance appeared to be well-dependent on the gas concentration, with the detection limit not worse than 100 ppm (no measurements were yet performed in the lower concentration range).…”

mentioning

confidence: 99%

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Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

et al. 2014

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Nanostructured niobium oxide (NO) semiconductor is gaining increasing attention as electronic, optical, and electro-optic material. However, the preparation of stable NO nanofilms with reproducible morphology and behavior remains a challenge. 10Here we show a rapid, well-controlled, and efficient way to synthesize NO films with the self-organized columnlike nanostructured morphologies and advanced functional properties. The films are developed via the growth of a nanoporous anodic alumina layer, followed by the pore-directed 15 anodizing of the Nb underlayer. The columns may grow 30-150 nm wide, up to 900 nm long, with the aspect ratio up to 20, being anchored to a thin continuous oxide layer that separates the columns from the substrate. The as anodized films have a graded chemical composition changing from amorphous Nb 2 O 5 mixed with Al 2 O 3 , Si-, and P-containing species in the surface region to NbO 2 in the lower film layer. The post-anodizing treatments result in the controlled 20 formation of Nb 2 O 5 , NbO 2 , and NbO crystal phases, accompanied by transformation from nearly perfect dielectric to n-type semiconductor behavior of the films. The approach allows for the smooth film growth without early dielectric breakdown, stress-generated defects, or destructive dissolution at the respective interfaces, which is a unique situation in the oxide films on niobium. The functional properties of the NO films, revealed to date, allow for potential applications as nanocomposite capacitor dielectrics and active 25 layers for semiconductor gas microsensors with the sensitivity to ethanol and the response to hydrogen being among best ever reported.

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Section: The Model Of Film Growthmentioning

confidence: 76%

Section: Film Compositionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

et al. 2014

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“…NbC niobium carbides (Figure 5b) exhibit the best electrochemical performance, in part because they constitute the system that has a lower degree of porosity, and also because the metal oxide Nb 2 O 5 has excellent chemical stability and corrosion resistance in acidic and basic media [22].…”

Section: Electrochemical Performancementioning

confidence: 99%

Electrochemical and wear behavior of niobium-vanadium carbide coatings produced on AISI H13 tool steel through thermo-reactive deposition/diffusion

Castillejo

Flórez

Orjuela

2016

Ingeniare. Rev. chil. ing.

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We deposited of niobium-vanadium carbide coatings on tool steel AISI H13 using the thermo-reactive substrates deposition/diffusion (TRD) technique. The carbides were obtained using salt baths composed of molten borax, ferroniobium, vanadium and aluminum, by heating this mixture at 1020° C for 4 hours. The coatings were characterized morphologically via electron microscopy scanning (SEM), the chemical surface composition was determined through X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX); the crystal structure was analyzed using x-ray diffraction (XRD), the mechanical properties of the coatings were evaluated using nano-indentation, The tribological properties of the coatings obtained were determined using a Pin-on-disk tribometer and the electrochemical behavior was studied through potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the hardness of the coated steel increased four times with respect to uncoated steel, and the electrochemical test established that the corrosion current is lower by one order of magnitude for coated steel.Keywords: Coatings, thermo reactive, niobium-vanadium carbide, spectroscopy, impedance. RESUMEN En este trabajo se depositaron recubrimientos de carburo de niobio-vanadio sobre aceros para herramientas AISI H13 utilizando la técnica de depósito por difusión termorreactiva (TRD). Los carburos se obtuvieron utilizando baños de sales compuestas de bórax fundido, ferroniobio, vanadio y aluminio, calentando la mezcla a 1020 °C durante 4 horas. Los recubrimientos fueron caracterizados morfológicamente mediante microscopia electrónica de barrido (SEM), la composición química de la superficie se determinó mediante espectroscopia de fotoelectrones de rayos X (XPS) y la espectroscopia de rayos X de energía dispersiva (EDX); la estructura cristalina se analizó utilizando difracción de rayos X (XRD), las propiedades mecánicas de los recubrimientos fueron evaluados utilizando nanoindentación. Las propiedades tribológicas de los recubrimientos obtenidos fueron determinadas usando un tribómetro Pin on Disk CETR-UMC-2 y el comportamiento electroquímico se estudió por medio de curvas de polarización potenciodinámica y espectroscopia de impedancia electroquímica (EIS). Los resultados mostraron que la dureza del acero revestido aumentó cuatro veces respecto del acero no recubierto, y la prueba electroquímica estableció que la corriente de corrosión es inferior en un orden de magnitud para el acero recubierto.Palabras clave: Recubrimientos, termorreactiva, carburo de niobio-vanadio, espectroscopia, impedancia.

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Tribocorrosion of different biomaterials under reciprocating sliding conditions in artificial saliva

Vilhena

Oppong

Ramalho

2019

Lubrication Science

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It has been found in recent studies that the main reason for the failure of a biomedical material used as an implant is due to the low resistance of the combined wear and corrosion. The aim of the present research study is to investigate the triboelectrochemical behaviour of different biomedical materials used as implants under different contact conditions. Comparative experiments were performed using commercial pure titanium (cP‐Ti), Ti6Al4V alloy, pure niobium (Nb), and a Co28Cr6Mo alloy sliding against a Zirconia counterbody tested in artificial saliva. The corrosion potential of the working electrode was monitorised using the open circuit potential technique, and potentiodynamic polarization curves were obtained. It was found that the Nb specimen showed a poor tribological performance, while the Co28Cr6Mo alloy showed the lowest friction and wear. The cP‐Ti specimen showed a more noble behaviour than that of the other three specimens with the highest corrosion potential value.

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Amorphous niobium oxide thin films

Cited by 88 publications

References 64 publications

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

Electrochemical and wear behavior of niobium-vanadium carbide coatings produced on AISI H13 tool steel through thermo-reactive deposition/diffusion

Tribocorrosion of different biomaterials under reciprocating sliding conditions in artificial saliva

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